Loans and Allowance for Loan Losses - Nonaccrual and Past Due Loans (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013 Loans	Dec. 31, 2012 Loans
Financing Receivable, Recorded Investment, Past Due
Financing receivables on nonaccrual status	$ 23,712	$ 22,817
Total number of loans on nonaccrual status	207	315
Past due Loans, Aging Analysis
30 to 59 Days Past Due	6,623	13,943
60 to 89 Days Past Due	786	2,000
Greater Than 90 Days	9,740	13,362
Total Past Due	17,149	29,305
Current	1,286,066	1,279,067
Loans	1,303,215	1,308,372
Real Estate Loans | Construction Loans
Financing Receivable, Recorded Investment, Past Due
Financing receivables on nonaccrual status	7,574	7,385
Past due Loans, Aging Analysis
30 to 59 Days Past Due	1,435	4,395
60 to 89 Days Past Due	0	345
Greater Than 90 Days	2,026	1,865
Total Past Due	3,461	6,605
Current	129,739	125,376
Loans	133,200	131,981
Real Estate Loans | Owner Occupied
Financing Receivable, Recorded Investment, Past Due
Financing receivables on nonaccrual status	5,211	5,787
Past due Loans, Aging Analysis
30 to 59 Days Past Due	593	838
60 to 89 Days Past Due	147	114
Greater Than 90 Days	3,013	4,237
Total Past Due	3,753	5,189
Current	353,202	337,773
Loans	356,955	342,962
Real Estate Loans | Non-owner Occupied
Financing Receivable, Recorded Investment, Past Due
Financing receivables on nonaccrual status	2,561	1,697
Past due Loans, Aging Analysis
30 to 59 Days Past Due	85	1,688
60 to 89 Days Past Due	0	500
Greater Than 90 Days	756	1,098
Total Past Due	841	3,286
Current	204,633	208,203
Loans	205,474	211,489
Real Estate Loans | One to Four Family
Financing Receivable, Recorded Investment, Past Due
Financing receivables on nonaccrual status	3,027	3,123
Past due Loans, Aging Analysis
30 to 59 Days Past Due	3,119	2,767
60 to 89 Days Past Due	584	910
Greater Than 90 Days	1,215	2,226
Total Past Due	4,918	5,903
Current	161,647	162,708
Loans	166,565	168,611
Real Estate Loans | Multifamily
Financing Receivable, Recorded Investment, Past Due
Financing receivables on nonaccrual status	268	539
Past due Loans, Aging Analysis
30 to 59 Days Past Due	0	12
60 to 89 Days Past Due	9	0
Greater Than 90 Days	0	10
Total Past Due	9	22
Current	34,352	35,315
Loans	34,361	35,337
Real Estate Loans | Home Equity Lines of Credit
Financing Receivable, Recorded Investment, Past Due
Financing receivables on nonaccrual status	2,005	1,041
Past due Loans, Aging Analysis
30 to 59 Days Past Due	831	1,980
60 to 89 Days Past Due	31	52
Greater Than 90 Days	42	924
Total Past Due	904	2,956
Current	192,500	188,932
Loans	193,404	191,888
Commercial
Financing Receivable, Recorded Investment, Past Due
Financing receivables on nonaccrual status	2,756	2,790
Past due Loans, Aging Analysis
30 to 59 Days Past Due	245	2,027
60 to 89 Days Past Due	2	34
Greater Than 90 Days	2,638	2,660
Total Past Due	2,885	4,721
Current	160,440	169,719
Loans	163,325	174,440
Consumer and other
Financing Receivable, Recorded Investment, Past Due
Financing receivables on nonaccrual status	310	455
Past due Loans, Aging Analysis
30 to 59 Days Past Due	315	236
60 to 89 Days Past Due	13	45
Greater Than 90 Days	50	342
Total Past Due	378	623
Current	49,553	51,041
Loans	$ 49,931	$ 51,664